• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.46-54
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• 1996

This study was carried out to investigate the vacuum drying characteristics of 50mm- and 75mm- thick tree disks of some domestic softwoods for substituting the conventional hardwoods as the materials for wood crafts. Though the elapsed drying times from green to in-use moisture content(MC) were largely shortened by vacuum drying, the tree disks treated by EWS couldn't be dried to in-use MC, and so sapwood stains also were occurred severely. We suggest EWS treatment is undesirable for the species with very high sapwood portion or vacuum drying with hot water circulation heating system. Heart checks were slight, but sapwood checks, which have never been trouble in drying process of tree disks, were severe. For the reasonable explanation it is suggested MC differences between sapwood and heartwood were large and most of tree disks had already no barks before drying test. Ginkgo was vacuum-dried with very slight drying defects such as heart checks, sapwood checks. V-cracks and sapwood stains. In Korean red pine and pitch pine V-cracks were severely occurred. And it was found the special feature that most of these defected tree disks contained several V-cracks within one tree disk. It can be considered as the causes that the region of sapwood was defected by the several checks at the early drying stage because of the steep MC gradient along the radial direction, and then at the later drying stage the drying stresses due to differential shrinkage were concentrated on these brittle spots.

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.125-131
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• 2011

The characteristics of radio-frequency/vacuum drying Japanese larch boxed heart round logs with 150 mm and 210 mm in diameter and 2,500 mm in length, subjected to compressive loading, after the pretreatment of kerf were investigated. The results of this study were as the follows: The drying time of about 120 hours~130 hours was needed from green to about 15 percent of moisture content. The gradient of final moisture content for all specimens was very gentle in both longitudinal and transverse directions owing to dielectric heating. The surface checks seriously occurred although the occurrence extent of surface check for the kerfed specimens was slight compared with that for the control specimens because drying stress was relieved by kerf. The occurrence of surface checks for the L-specimen was more serious than that for the S-specimen.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.7-14
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• 2006

Three-dimensional distribution and variation of moisture content of boxed-heart square timber of Pinus densiflora was investigated to find the safe and rapid drying methods. As results, microwave-drying method could dry the boxed-heart square timber with sectional dimension of $150{\times}150mm$ under 10% moisture content (MC) within 72 hours with less surface checks, compared with hot-air drying. In case of microwave drying, the MC distribution during drying had a close relation with the initial MC distribution. In case of hot air drying, however, it was independent on the intial one except for the intial drying stage.

• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.345-363
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• 2020

This study was conducted to identify the effect of kerfing and incising pretreatments on high-temperature drying characteristics of cedar and larch boxed-heart timbers with a cross section of less than 150 mm. The result showed that the pretreatments have made a significant difference regarding surface check and shrinkage. Although the kerfing was suitable as a pretreatment to reduce the occurrence of surface check, the incising was not suitable as a pretreatment since the knives of timber joined together, causing the conversion to the surface checks. The shrinkage showed a significant result that the final moisture content was reduced in the order of incising, kerfing, and kerfing-incising after the drying process based on the pretreatment condition. Twist was more affected by the grain angle than the anisotropy of the juvenile wood, and there was no effect of pretreatments.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.139-145
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• 2023

When a doctor examines a patient in a hospital, the doctor directly checks the patient's condition and conducts a face-to-face diagnosis through dialogue with the patient. However, it is often difficult for doctors to directly treat patients. Recently, several types of telemedicine systems have been developed. However, the systems have lack of capabilities to observe heart disease, neck condition, skin condition, inside ear condition, etc. To solve this problem, in this paper, an interactive telemedicine robot system with autonomous driving in a room capable of visual examination and auscultation of patients is developed. The developed robot can be controlled remotely through the WebRTC platform to move toward the patient and check a patient's condition under the doctor's observation using the multi-joint robot arm. The video information, audio information, patient's heart sound, and other data obtained remotely from patients can be transmitted to a doctor through the web RTC platform. The developed system can be applied to the various places where doctors are not possible to attend.

• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.121-135
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• 2020

This study aims to evaluate applicability for the continuous drying process using saturated and superheated steam for large-square timber. During drying of the boxed heart square timber, changes in moisture content were examined through the slices of the surface, inner and core layers. The results showed that there was a large moisture content difference between the surface and inner layers during saturated steam drying and between the inner and core layers during superheated steam drying. However, despite the moisture content difference between the layers, no surface check occurred, and an internal check occurred only near the pith or juvenile parts of the wood. The maximum value of the drying stress of the dried larch boxed heart square timber, calculated from the elastic strain of the slice and the tangential elastic modulus of the larch, was 1.30 MPa. The tangential tensile strength of the larch was estimated at 5.21 MPa under temperature and moisture content conditions when drying stress was at a maximum. That is, in the continuous drying process, the saturated and superheated steam did not generate a check in the surface because the drying stress of the wood did not exceed the tangential tensile strength. In further studies, the superheated steam drying conditions will need to be relaxed to suppress the occurrence of internal checks. Such studies would make the continuous drying process using saturated and superheated steam available for the drying of large-square timber.

• Journal of Chest Surgery
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• v.11 no.1
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• pp.102-107
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• 1978

This is a report of a chylous cyst in the mediastinum found in a 61 year old Korean female patient who suffered from mild swallowing difficulty and right chest discomfort. These symptoms had developed 5 years previously when chest P-A view showed thumb-tip sized mass shadow in right mediastinum, just right to ascending aorta. Esophagogram revealed an indentation of midesophagus. Follow up checks showed growing mass shadow which suggested aneurysm of ascending aorta. On admission chest X-ray revealed a well circumscribed infant head sized mass density along the right heart border and middle mediastinal border, and extended near to the middle clavicular line in right chest cavity. Aortogram revealed no relationship between the mass and aorta. Right thoracotomy was performed under impression of mediastinal tumor. There was a large cyst containing 700 cc of milky fluid. There was no connection to the thoracic duct nor adjacent organs. The fluid was analyzed chemically and identified the fluid as chyle. The origin of the isolated chylous cyst was uncertain postoperative course was uneventful.

• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.456-465
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• 2013

Log cross sections of yellow poplar were dried in a radio frequency vacuum (RFV) dryer under alternating vacuum and release (AVR) process. The average moisture content (MC), temperature and vapor pressure at the volumetric center were monitored as functions of time. Three different log thicknesses (33, 60 and 75mm) were tested. The results show that the AVR process caused an increase in the drying rate when the moisture content was above fiber saturation point (FSP, about 30% MC) but that it had an inverse effect on the drying rate when the MC was below FSP. The effect of the AVR process on the drying rate decreased, and the severity of heart checks increased, with the increase in the thickness of the specimens.

• Journal of the Korean Wood Science and Technology
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• v.19 no.1
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• pp.31-63
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• 1991

It was proved that in conventional kiln drying of disks piling position in the kiln exerted a great influence on drying rates, and the larger the variation of disk diameter, the more undulating drying rates of disks. While in vacuum drying disks there was no influence on drying rates. By the end-wrapping treatments and the radial direction of disks tangential surface stresses in the core of disks were slightly compressive in three species. In control disks the drying stresses distributed into one step-style that compressive stresses in the pith side of 6cm from pith were larger than those in the bark side, while in the disks end-wrapped with Korean paper the drying stresses distributed uniformly, because flow rates of free water in disks had no difference between heart-and sap-wood by obstruction of evaporating water from surface of disks by end-wrapping with Korean paper. And end-wrapping with Korean paper considerably restrained those. Tangential differential shrinkage stresses developed the maximum tensile stress near the bark and with approaching the pith the stresses gradually reduced and changed into compressive stresses in near the pith. At the end of vacuum drying the maximum tangential tensile stresses of disks end-wrapped with Korean paper were smaller than those of control disks, and critical moisture contents causing the V-shaped crack of disks end-wrapped with Korean paper were lower than those of control disks because of the set by obstruction of evaporating water of end-wrapping with Korean paper. In the experiment of vacuum drying stress distribution the disks end-wrapped with Korean paper or aluminum foil in three species were free from V-shaped cracks and control disks were defected very slightly by V-shaped cracks. And also disks end-wrapped with Korean paper were free from heart checks in Alnus japonica and Juglans sinensis, and heart checks were occurred very slightly in others. Especially, not to speak of disks end-wrapped with Korean paper, vacuum drying of disks end-wrapped with aluminum foil prevented effectively drying defects, moreover drying times could be shortened, that is. Ginkgo biloba, Alnus japonica, and Juglans sinensis disks could be dried from green to in-use moisture content in 110 hours, 272 hours, and 407 hours, respectively.

• Journal of The Korean Dental Society of Anesthesiology
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• v.13 no.1
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• pp.13-18
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• 2013

CATCH 22 syndrome is a one of the most common chromosome microdeletion syndrome with multiple organ anomalies in humans, with an incidence of approximately 1:4,000 to 1:5,000 live births. It is caused by a microdeletion of 1.5 to 3.0 megabases on the long arm of chromosome 22. The phenotypic spectrum of this disorder is wide and various. A 19-year-old patient who showed delayed growth and development (Height; 110 cm, Weight; 18 kg) was referred to our department for the treatment of dental cavities. She was diagnosed as CATCH 22 syndrome in 2004. Physical examination revealed hypertelorism, a short philtrum, thick reflected lips and a small mouth. She underwent cleft palate surgery at 1 year of age and heart valve surgery due to the cardiovascular abnormality at 13 years of age. Convulsive seizures had persisted until 5 years ago but are well controlled at present. Oral examination showed poor oral hygiene, crowding, prolonged retention on #65, 75 and dental cavities on #16, 21, 65, 26, 36, and 46. Cavity treatment and prophylaxis were performed under general anesthesia. Also continuous follow-up checks have been carrying out with the periodic prophylaxis and dental home education. Problems with numerous cavities and gingivitis which can lead to specific risks are common for CATCH 22 syndrome patients. It is therefore of great importance that these patients are referred to foremost physician and dental specialist for the oral care. In addition, preventive treatment targeting the risk of dental cavities and gingivitis is especially important and, as the syndrome involves many different medical problems, the dental treatment should be carried out in collaboration with the patient's physician.